Scroll Compressor

ABSTRACT

In a scroll compressor, it is hard to zone a high pressure chamber and a back pressure chamber which are formed in a back face of an orbiting scroll by a sealing means, increase a feeding amount to the high pressure chamber and the back pressure chamber at a low speed and adjust it at a high speed. A sealing means sealing a high pressure chamber in a center portion of a back face of an orbiting scroll and a back pressure chamber formed by an outer peripheral portion is provided, and a spiral shaped throttle passage is provided between a boss portion in the back face of the orbiting scroll and an outer peripheral surface of an orbiting bearing, thereby constructing an oil feeding route for feeding a lubricating oil to the back pressure chamber from the high pressure chamber.

BACKGROUND OF THE INVENTION

(1) Field of the Invention

The present invention relates to a scroll compressor which handles an HFC type cooking medium, an air and a carbon dioxide corresponding to a natural refrigerant, and the other compressible gas, and more particularly to a scroll compressor which zones a high pressure chamber (having an approximately equal pressure to a discharge pressure) which is constructed by a back face side of an orbiting scroll and a back pressure chamber (a pressure space having a lower pressure than the discharge pressure) by a sealing means in a pressure manner.

(2) Description of the Related Art

A so-called high pressure chamber type scroll compressor is provided with a crank shaft which has a crank portion, an orbiting scroll which has an orbiting bearing to which the crank portion is inserted, and a fixed scroll which forms a compression chamber by being engaged with the orbiting scroll, and changes a volumetric capacity of the compression chamber so as to compress the refrigerant by pressing the orbiting scroll to the fixed scroll on the basis of a pressure of the back pressure chamber and turning the orbiting scroll on the basis of a rotation of the crank shaft.

In patent document 1 (JP-A-2003-176794), there is described “it is structured such that a lubricating oil is intermittently fed by setting a sealing means for sealing a high pressure chamber in the periphery of a center portion of a back face of an orbiting scroll and a back pressure chamber (a low pressure chamber) which is formed by an internal space of an outer periphery in a frame inner peripheral surface which is opposed to an end surface of a boss portion of the back face of the orbiting scroll, and setting a small hole which retains the lubricating oil in the end surface of the boss portion, thereby reciprocating the high pressure chamber in the periphery of the center portion of the back face of the orbiting scroll and the back pressure chamber while being astride the sealing means. In accordance with this, an amount of the lubricating oil which is fed to the back pressure chamber from the high pressure chamber is adjusted, an efficiency of the compressor can be widely improved, and it is also possible to improve a reliability of the compressor.”

Further, in accordance with patent document 2 (JP-A-2002-168183), there is described “In a back pressure chamber in a back face side of an orbiting scroll, a lubricating oil is fed to an outer region (a low pressure chamber) from an inner region (a high pressure chamber) which is zoned by a seal member, and a plug member forming a spiral throttle passage which depressurizes the lubricating oil fed from the inner region so as to feed to an outer region is arranged in an orbiting scroll end plate surface. In accordance with this, on the basis of the spiral throttle passage rather than the straight throttle passage, it is possible to enlarge a cross sectional area of the passage only at a rate that a length of the passage can be set longer, and it is possible to achieve a stabilization of the compressor which is hard to generate an occlusion due to a foreign particle existing in the lubricating oil and has a high efficiency.”

In accordance with the known art in the patent document 1, in the scroll compressor, it is general to form a vertical structure in which a compression mechanism portion is positioned above and an electric motor portion is positioned below, and it is structured such that the lubricating oil is intermittently fed by setting the sealing means for sealing the high pressure chamber in the center portion of the back face boss portion of the orbiting scroll and the back pressure chamber (the low pressure chamber) which is formed by the internal space of the outer periphery in the frame inner peripheral surface which is opposed to the end surface of the boss portion of the back face of the orbiting scroll, and setting the small hole which retains the lubricating oil in the end surface of the boss portion, thereby reciprocating while being astride the sealing means which zones the high pressure chamber and the back pressure chamber.

In recent years, since an energy saving has been desired, and an annual performance factor (APF) has been displayed as an index thereof, an importance of a low speed condition which is called as an intermediate condition has been increased. In order to improve an efficiency of a compressor under the low speed condition, it is effective to increase an oil feeding amount to the compression mechanism portion so as to improve a sealing performance. In accordance with this, in a method of intermittently feeding the lubricating oil by means of the small hole or the like which is provided in the end surface of the boss portion in the back face of the orbiting scroll in the case of being operated under the low speed condition, since the oil feeding amount is increased while depending on a turning speed, it is necessary to increase the number of the small holes in such a manner that it is possible to secure a necessary amount for enhancing an efficiency under the low speed condition.

However, if the number of the small holes is increased for enhancing the efficiency under the low speed condition, the oil feeding amount to the back pressure chamber becomes excessive in the case of being operated under the high pressure condition, and there are such problems that an increase of an agitating loss of the orbiting scroll carrying out a turning motion in the back pressure chamber lowers the efficiency of the compressor, and the oil is mixed into the gas discharged from the compression chamber and an amount of the oil which is conducted out of the discharge pipe to the cycle is increased so as to make it impossible to retain the oil in the compressor.

Further, in accordance with the known art in the patent document 2, in the back pressure chamber in the opposite side to the spiral lap surface of the orbiting scroll, in order to feed the lubricating oil to the inner region and the outer region which are zoned by the sealing member so as to backup the orbiting scroll part, and prevent the orbiting scroll part from being far from the fixed scroll part so as to be turned over, it is structured such that a cross sectional area of the throttle passage can be set larger at a rate at which the throttle portion depressurizing the lubricating oil from the inner region so as to feed through the outer region can set a peripheral length longer in the spiral throttle passage.

However, if the plug member provided with the spiral throttle passage is inserted to the end plate surface of the orbiting scroll, there is a limit for setting a cross sectional area larger by enlarging a length of the throttle passage, due to a dimensional constraint of a diameter size and a length of the plug member, and there are such problems that a dispersion of the oil feeding amount becomes larger unless the cross sectional area of the throttle passage is worked at a high precision, and an efficiency is lowered.

Further, since it is structured such that the seal member is arranged in the back face of the orbiting scroll end plate, it has a lubricating oil reservoir in addition to an upper lubricating oil reservoir in the high pressure orbiting bearing upper space in the inner region of the seal member, and there is such a problem that a loss in agitating the lubricating oil becomes larger on the basis of the turning motion of the orbiting scroll in the space portion of the lubricating oil reservoir, and an efficiency becomes lowered.

There is such a method of feeding a lubricating oil to a back pressure chamber after feeding the lubricating oil to an orbiting bearing and a main bearing, by means of a differential pressure oil feeding type pump, without using any displacement type pump for the oil feeding pump. In the case of this oil feeding type, the oil feeding amount is suppressed on the basis of a depressurizing effect caused by a gap of a sliding bearing or the like, and is carried out by controlling a bearing gap. In this case, set values of a diameter and a gap of the sliding bearing are generally set such that a rate of gap/diameter is 0.001, and if the bearing diameter size becomes larger, the bearing gap becomes of course wider and the oil feeding amount fed to the back pressure chamber is increased.

Since the oil feeding amount is in proportion to a cubic of the bearing gap, there is a limit for controlling an appropriate oil feeding amount by the bearing gap, and it becomes very hard. On the basis of the background mentioned above, it is more easily control the oil feeding amount to the back pressure chamber by a scroll compressor which zones a high pressure chamber (having an approximately equal pressure to a discharge pressure) which is constructed in a back face side of an orbiting scroll, and a back pressure chamber (a pressure space having a lower pressure than the discharge pressure) by a seal means in a pressure manner, and uses a displacement type pump or a centrifugal pump for the oil feeding pump. If the oil feeding amount can be appropriately controlled, it is possible to improve an efficiency.

BRIEF SUMMARY OF THE INVENTION

An object of the present invention is to provide a compressor having a high efficiency.

The object mentioned above can be achieved by a scroll compressor provided with a compression chamber formed by engaging a fixed scroll and an orbiting scroll with each other, each of which has an end plate and a spiral lap provided in a rising manner in the end plate, a crank shaft making the orbiting scroll carry out a turning motion, an orbiting bearing portion engaging the orbiting scroll and an eccentric pin portion of the crank shaft so as to be movable in a direction of a rotating axis and be rotatable and provided in a back face of the orbiting scroll, a main bearing portion arranging a support portion which rotatably engages the crank shaft in a center portion of a frame member, a back pressure chamber zoned by a seal member which is arranged between the back face of the orbiting scroll and the frame member, and a high pressure chamber zoned in an inner side of the seal member being maintained at a pressure which is approximately equal to a discharge pressure, in which the back pressure chamber zoned in an outer side of the seal member is maintained at a pressure which is lower than the discharge pressure, wherein a spiral shaped groove passage is formed in an outer peripheral surface of the orbiting bearing, and a throttle passage communicating with the back pressure chamber is arranged so as to be provided with such the throttle passage as to be capable of continuously feeding a lubricating oil to the back pressure chamber from the high pressure chamber.

In the scroll compressor in accordance with the present invention, it is preferable that the spiral shaped groove passage is formed in an inner peripheral surface of a boss portion in the back face of the orbiting scroll, and the throttle passage communicating with the back pressure chamber is arranged so as to be provided with such the throttle passage as to be capable of continuously feeding the lubricating oil to the back pressure chamber from the high pressure chamber.

In the scroll compressor in accordance with the present invention, it is preferable that the spiral shaped groove passage is formed in an outer peripheral surface of the orbiting bearing, and the throttle passage communicating with an end surface of a turning boss portion is arranged so as to be provided with such the throttle passage as to be capable of intermittently feeding the lubricating oil to the back pressure chamber from the high pressure chamber.

In the scroll compressor in accordance with the present invention, it is preferable that the spiral shaped groove passage is formed in an inner peripheral surface of a boss portion in a back face of the orbiting scroll, and the throttle passage communicating with an end surface of a turning boss portion is arranged so as to be provided with such the throttle passage as to be capable of intermittently feeding the lubricating oil to the back pressure chamber from the high pressure chamber.

In the scroll compressor in accordance with the present invention, it is preferable that the orbiting bearing employs a winding bush which is formed as a cylindrical shape by rolling a flat plate, and a groove which is diagonal in a state of the flat plate or a rectangular groove is applied in accordance with a press molding or an etching process.

Further, the object mentioned above can be achieved by a scroll compressor provided with a crank shaft having an eccentric pin portion, an orbiting scroll having an orbiting bearing to which the eccentric pin portion is inserted, a fixed scroll forming a compression chamber by being engaged with the orbiting scroll, and a volumetric capacity of the compression chamber being changed by pressing the orbiting scroll to the fixed scroll on the basis of a pressure of a back pressure chamber and turning the orbiting scroll on the basis of a rotation of the crank shaft so as to compress a refrigerant, wherein a high pressure chamber is formed between an end surface of the eccentric pin portion and a back face of the orbiting scroll, a throttle passage is provided between the eccentric pin portion and the orbiting bearing, and the orbiting scroll is provided with a discharge passage which introduces an oil to the back pressure chamber from the high pressure chamber via the throttle passage.

In the scroll compressor in accordance with the present invention, it is preferable that the throttle passage is formed as a spiral shape.

EFFECT OF THE INVENTION

In accordance with the present invention, it is possible to enhance an efficiency.

Other objects, features and advantages of the invention will become apparent from the following description of the embodiments of the invention taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

FIG. 1 is a view of a whole structure of a scroll compressor in accordance with a first embodiment;

FIG. 2 is an enlarged view in the vicinity of a boss portion of an orbiting scroll in accordance with the first embodiment;

FIG. 3 is an explanatory view of an effect in connection with an oil feeding amount of a back pressure chamber;

FIG. 4 is an explanatory view of an effect in connection with an efficiency;

FIG. 5 is an enlarged view in the vicinity of a boss portion of an orbiting scroll in accordance with a second embodiment;

FIG. 6 is an enlarged view in the vicinity of a boss portion of an orbiting scroll in accordance with a third embodiment;

FIG. 7 is an enlarged view in the vicinity of a boss portion of an orbiting scroll in accordance with a fourth embodiment;

FIG. 8 is a cross sectional view of an assembled state of the boss portion of the orbiting scroll in accordance with the first embodiment;

FIG. 9 is a cross sectional view of an assembled state of the boss portion of the orbiting scroll in accordance with the second embodiment;

FIG. 10 is an expansion plan view before rolling an orbiting bearing in accordance with a fifth embodiment; and

FIG. 11 is an enlarged view in the vicinity of a boss portion of an orbiting scroll in accordance with a conventional art.

DETAILED DESCRIPTION OF THE INVENTION

A description will be in detail given below of embodiments in accordance with the present invention with reference to the accompanying drawings.

Embodiment 1

A description will be given in detail of a scroll compressor which shows a first embodiment in accordance with the present invention, with reference to FIG. 1 and FIG. 2. A description will be given of a whole structure of the scroll compressor showing the first embodiment in accordance with the present invention.

A scroll compressor 1 is constructed by storing a compression mechanism portion 2 and a driving portion 3 within a sealed container 100. The compression mechanism portion 2 is constructed by a fixed scroll 110, an orbiting scroll 120 and a frame 160. The fixed scroll 110 has an end plate 110 b and a spiral lap 110 a which is provided in a rising manner so as to be vertical to the end plate 110 b, has a discharge port 110 e in a center portion of the lap, and is fixed to the frame 160 via a plurality of bolts. The orbiting scroll 120 has an end plate 120 b and a spiral lap 120 a which is provided in a rising manner so as to be vertical to the end plate 120 b, and is constructed in a back face side of the end plate 120 b by a boss portion 120 e and a boss portion end surface 120 f.

A compression chamber 130 constructed by engaging the fixed scroll 110 and the orbiting scroll 120 carries out such a compression motion that a volumetric capacity thereof is reduced on the basis of a turning movement of the orbiting scroll 120. In this compression motion, a working fluid is sucked into the compression chamber 130 from a suction port 140 in connection with the turning movement of the orbiting scroll 120, and the sucked working fluid is discharged to a discharge space 136 within the sealed container 100 from the discharge port 110 e of the fixed scroll 110 via a compression stroke, and is further discharged from the sealed container 100 via a discharge port 150. In accordance with this, a space within the sealed container 100 is kept at a discharge pressure. The compressor mentioned above is called as a so-called high pressure chamber type.

The driving portion 3 making the orbiting scroll 120 carry out a turning movement is constructed by a stator 108 and a rotor 107, a crank shaft 101, an Oldham's coupling 134 which corresponds to a main part of an autorotation preventing mechanism of the orbiting scroll 120, a frame 160, a main bearing 104, an auxiliary bearing 105, and an orbiting bearing 103. The crank shaft 101 is structured such as to be integrally provided with a main shaft portion 101 b and an eccentric pin portion 101 a. The main bearing 104 and the auxiliary bearing 105 are structured such as to rotatably engage the crank shaft 101. The orbiting bearing 103 is provided in the boss portion 120 e of the orbiting scroll in such a manner as to engage the eccentric pin portion 101 a of the crank shaft 101 so as to be movable in a direction of a rotating axis and be rotatable. The main bearing 104 and the auxiliary bearing 105 which rotatably engage the crank shaft are arranged in a side of the compression mechanism portion 2 which is constructed by the stator 108 and the rotor 107 and a side of an oil reservoir portion 131, respectively.

In the present embodiment, it is desirable that a sliding bearing is used in the main bearing 104 in the vicinity of the side of the compression mechanism portion 3, however, a rolling bearing may be used. However, the auxiliary bearing 105 in the vicinity of the oil reservoir portion 131 may employ a rolling bearing which can be adapted to a used condition or the other spherical bearing members, in addition to the illustrated sliding bearing. The Oldham's coupling 134 is arranged in a back pressure chamber 180 which is constructed by the orbiting scroll 120 and the frame 160, and is an autorotation preventing member of the fixed scroll 110 and the orbiting scroll 120. One set of two sets of orthogonal key portions which are formed in the Oldham's coupling 134 slides on a key groove which is constructed in the frame 160, and the remaining one set slides on a key groove which is constructed in the back face side of the orbiting scroll 120.

A description will be given of a sealing means separating into a high pressure chamber (having a pressure which is approximately equal to a discharge pressure) which is constructed in the back face side of the orbiting scroll 120, and a back pressure chamber (having a pressure which is lower than the discharge pressure), and a route feeding the oil from the high pressure chamber to the back pressure chamber, with reference to FIG. 1 and FIG. 2.

FIG. 2 is an enlarged view (a portion A in FIG. 1) in the vicinity of the high pressure chamber and the back pressure chamber in FIG. 1. A space constructed in the back face side of the orbiting scroll 120 is a space which is constructed by being surrounded by the orbiting scroll 120, the frame 160 and the fixed scroll 110. The separating means of the high pressure chamber and the back pressure chamber is structured such as to be provided with a boss portion end surface 120 f in the back face of the orbiting scroll, a frame end surface portion 164 which faces thereto, a ring-like groove 161 which is constructed in the end surface portion 164, and a seal member 172 which is arranged in the ring-like groove 161. In this case, the boss portion end surface 120 f is a seal surface which comes into contact with the seal member 172. The seal member 172 is a sealing means separating the back pressure chamber 180 and the high pressure chamber 181 in a pressure manner.

The high pressure chamber 181 is formed between an end surface of the eccentric pin portion 101 a of the crank shaft 101 and a back face of the orbiting scroll 120. The high pressure chamber 181 seals a lubricating oil which is discharged from the orbiting bearing 103, the main bearing 104 and a thrust bearing 204 by a seal member 172, and comes to a pressure space at an approximately discharge pressure while being exposed to a boosting action caused by a pumping action and a depressing action at a time of passing through the bearing portion and the gap portion. Since the sliding portion such as the Oldham's coupling 134 or the like arranged within the back pressure chamber 180 feeds a part of the lubricating oil fed to the high pressure chamber 181, the lubricating oil in the high pressure chamber 181 is depressurized by passing through a groove 200 a which corresponds to a spiral shaped throttle passage arranged in an outer peripheral surface of the boss portion 120 e and the orbiting bearing 103, and lubricating oil is continuously fed to the back pressure chamber 180 through a discharge passage 201 which is communicated with the back pressure chamber 180. In other words, the discharge passage 201 introduces the lubricating oil to the back pressure chamber 180 from the high pressure chamber 181 via the throttle passage, that is, the groove 200 a. In this case, as illustrated, the discharge passage 201 is provided in the orbiting scroll 120.

A description will be given of an assembled state in accordance with the first embodiment with reference to FIG. 8. The spiral formed groove 200 a can be formed only by forming the groove 200 a on an open outer peripheral surface of the orbiting bearing 103 before being fitted between the members in which the outer peripheral surface of the boss portion 120 e and the inner peripheral surface of the orbiting bearing 103 are fitted to each other, and carrying out the fitting of the orbiting bearing 103 to the boss portion 120 e. Particularly, if the orbiting bearing 103 is constructed as a cylindrical member, a process of the spiral formed groove 200 a can be carried out by a comparatively easy turning machine process or the like. Therefore, a low cost can be achieved.

A description will be given of an effect of the present embodiment. It is possible to feed a part of the lubricating oil in the high pressure chamber 181 into the back pressure chamber 180 through the discharge passage 201 while effectively depressurizing the lubricating oil in the high pressure chamber, on the basis of a pressure loss caused by a pipe line friction of a flow path of the groove 200 a which is installed on the outer peripheral surface of the boss portion 120 e and the orbiting bearing. Accordingly, under a low speed condition, the oil feeding amount is increased, and it is possible to enhance an efficiency of the compressor by improving a sealing performance within the compression chamber 130. Further, under a high speed condition, on the basis of the oil feeding system in which the spiral formed groove 200 a depending on a pressure difference is dominant, it is possible to appropriately control the oil feeding amount, it is possible to widely reduce an oil rising amount which is introduced out to the cycle, and it is possible to retain the oil within the compressor. Therefore, it is possible to achieve a high efficient compressor.

However, in the conventional one, as shown in FIG. 11, since a small hole 170 which is arranged in the boss portion end surface 120 f reciprocates an inner side and an outer side of the sealing member 172 so as to feed a part of the lubricating oil in the high pressure chamber 181 to the back pressure chamber 180, it is an oil feeding method which depends on the rotating speed, the oil feeding amount runs short under the low speed condition, and the oil feeding amount becomes excessive under the high speed condition.

A description will be given of a result obtained by comparing an effect in the present embodiment with the conventional one with reference to FIG. 3. The drawing shows a relationship between a rotational frequency and an amount ratio of oil supply. In this case, there is shown the amount ratio of oil supply on the basis of an oil feeding amount under a rated condition (a rotational frequency: 60 Hz). In the conventional oil feeding system by the small hole, since the oil feeding amount fluctuates while depending on the rotating speed, the oil feeding amount under the high speed condition is increased more than necessary if it is intended to increase the oil feeding amount under the low speed condition, for example, the condition that the rotational frequency is 20 Hz.

On the contrary, since the structure in accordance with the present embodiment is of the type which depends on the pressure difference, and can retain the oil feeding amount constant in a range from the low speed condition to the high speed condition, it is possible to increase the oil feeding amount under the low speed condition without coming to an excessive oil feeding amount in comparison with the conventional one under the high speed condition. In other words, it is possible to improve an efficiency of the compressor in a low speed operation corresponding to an intermediate condition, and an excessive oil feeding under the high speed condition is not caused, it is possible to reduce an agitating loss of the orbiting scroll and reduce an amount of the oil which is derived out of the discharge pipe to the cycle. Therefore, it is possible to achieve a scroll compressor which can secure both sides of a reliability and an efficiency.

FIG. 4 describes an efficiency and an effect in accordance with the present embodiment. The present drawing shows a compressor efficiency ratio between the present embodiment and the conventional structure in a half-load cooling condition and a rated cooling condition under an APF condition. In this case, the compressor efficiency ratio is based on the conventional efficiency. On the basis of the spiral formed throttle passage in accordance with the present embodiment, the half-load cooling condition having a high rate of contribution can improve the efficiency 2% more than the conventional oil feeding system by the small hole, and approximately the same efficiency can be maintained under the rated cooling condition. Accordingly, it is possible to achieve the scroll compressor in which an energy compressor efficiency ratio is good all year.

As mentioned above, the throttle passage which can continuously feed the lubricating oil from the high pressure chamber to the back pressure chamber is provided by arranging the discharge passage which communicates with the spiral shaped groove and the back pressure chamber between the orbiting scroll boss portion and the orbiting bearing. In other words, the structure is made such that the throttle passage which can continuously feed the lubricating oil from the high pressure chamber to the back pressure chamber is provided by arranging the throttle passage which communicates with the spiral shaped groove and the back pressure chamber between the orbiting scroll boss portion and the orbiting bearing. In accordance with the present embodiment, the spiral shaped groove passage having a predetermined length extends along the outer peripheral surface of the orbiting bearing, and the high pressure chamber and the back pressure chamber are communicated via the throttle passage. It is possible to make a length of the flow path of the lubricating oil long, by forming the throttle passage as mentioned above, and it is possible to effectively depressurize the lubricating oil in the high pressure chamber on the basis of the pressure loss caused by the pipe line friction of the flow path so as to feed to the back pressure chamber.

Accordingly, it is possible to increase the feeding amount at the low speed, and it is possible to appropriately control the feeding amount at the high speed. In other words, it is possible to improve the efficiency of the compressor in the low speed operation which is closer to the intermediate condition than the conventional one, and it is possible to prevent the oil feeding amount in the high speed condition from becoming excessive. As mentioned above, since it is possible to achieve the high efficiency of the compressor and widely reduce the rate at which the oil is mixed into the gas which is discharged in the high speed condition, by increasing the oil feeding amount in the low speed condition and adjusting the oil feeding amount in the high speed condition, it is possible to widely reduce the oil rising amount which is derived out to the cycle, and it is possible to retain the oil within the compressor.

Embodiment 2

A description will be given of a scroll compressor showing a second embodiment in accordance with the present invention with reference to FIG. 5 and FIG. 9. FIG. 5 is a cross sectional view in the vicinity of an orbiting scroll boss portion. FIG. 9 shows a cross sectional view of an assembled state in the vicinity of the boss portion of a back face of the orbiting scroll. In this case, the other than the installing means of the spiral shaped groove arranged in the orbiting scroll boss portion is the same as the first embodiment, and a description will be given of only a different portion.

The structure is made such as to be provided with a throttle passage which can continuously feed the lubricating oil from the high pressure chamber 181 to the back pressure chamber 180 by forming a spiral shaped groove 200 b in an outer peripheral surface of the boss portion 120 e of the orbiting bearing 103, and arranging the discharge passage 201 which communicates with the back pressure chamber 180.

On the basis of the constructing means as mentioned above, it is possible to increase the feeding amount of the lubricating oil to the high pressure chamber 181 and the back pressure chamber 180 at a low speed, and appropriately control the feeding amount at a high speed, it is possible to improve the efficiency of the compressor in the low speed operation which is closer to the intermediate condition than the conventional structure, and it is possible to prevent the oil feeding amount from becoming excessive in the high speed condition. As mentioned above, since it is possible to achieve the high efficiency of the compressor and it is possible to widely reduce the rate at which the oil is mixed into the gas discharged in the high speed condition, by increasing the oil feeding amount in the low speed condition and adjusting the oil feeding amount in the high speed condition, it is possible to widely reduce the oil rising amount which is derived out to the cycle, and it is possible to retain the oil within the compressor.

In accordance with the present embodiment, the throttle passage of the spiral formed groove 200 b can be formed only by forming the spiral shaped groove 200 b on the inner peripheral surface of the boss portion 120 e before being fitted between the members in which the outer peripheral surface of the boss portion 120 e and the inner peripheral surface of the orbiting bearing 103 are fitted to each other, and carrying out the fitting of the orbiting bearing 103 to the boss portion 120 e. Particularly, since a process of the spiral formed groove 200 b on the inner peripheral surface of the turning boss portion can be carried out by a comparatively easy turning machine process or the like, a low cost can be achieved.

Embodiment 3

A description will be given of a scroll compression showing a third embodiment in accordance with the present invention with reference to FIG. 6. FIG. 6 shows a cross sectional view in the vicinity of the boss portion of the back face of the orbiting scroll. In this case, the other than the discharge passage arranged in the orbiting scroll boss portion is the same as the first embodiment, and a description will be given of only a different portion.

The structure is made such that the spiral shaped groove 200 a is formed on the outer peripheral surface of the boss portion 120 e and the orbiting bearing 103, and a throttle passage 202 communicating with the boss portion end surface 120 f is arranged, whereby if it reciprocates astride the seal member 172, the lubricating oil fed to the throttle passage 202 can be intermittently fed to the back pressure chamber 180 from the high pressure chamber 181. On the basis of the constructing means mentioned above, it is possible to increase the feeding amount of the lubricating oil to the high pressure chamber 181 and the back pressure chamber 180 at the low speed, and appropriately control the feeding amount at the high speed, it is possible to improve the efficiency of the compressor in the low speed operation which is closer to the intermediate condition than the conventional structure, and it is possible to prevent the oil feeding amount from becoming excessive in the high speed condition. As mentioned above, since it is possible to achieve the high efficiency of the compressor and widely reduce the rate at which the oil is mixed into the gas discharged in the high speed condition, by increasing the oil feeding amount in the low speed condition and adjusting the oil feeding amount in the high speed condition, it is possible to widely reduce the oil rising amount which is derived out to the cycle, and it is possible to retain the oil within the compressor.

On the basis of the intermediate oil feeding means such as the third embodiment, in comparison with the continuous oil feeding means such as the first embodiment, since the same depressurizing effect can be obtained even if a cross sectional area of the spiral shaped groove passage is further enlarged, it is possible to enlarge a dimensional tolerance of the cross sectional area of the spiral shaped groove passage. If the cross sectional area of the passage is enlarged, it is possible to suppress a dispersion of the oil feeding amount in comparison with the first embodiment, it is possible to further simplify a workability, and a cost reduction can be achieved.

The present embodiment is structured such that the throttle passage communicating with the spiral shaped groove and the end surface of the turning boss portion is arranged between the orbiting scroll boss portion and the orbiting bearing, and reciprocates astride the sealing means which zones the high pressure chamber and the back pressure chamber, whereby the throttle passage can intermittently feed the lubricating oil. On the basis of the constructing means mentioned above, since the same depressurizing effect can be obtained even if the cross sectional area of the passage is enlarged further in comparison with the continuous oil feeding means in accordance with the first invention, it is possible to hold down the dispersion of the oil feeding amount even if the dimensional tolerance of the cross sectional area of the passage is enlarged.

In accordance with this, it is possible to increase the feeding amount of the lubricating oil to the high pressure chamber and the back pressure chamber at the low speed, and appropriately control the feeding amount at the high speed. In other words, it is possible to improve the efficiency of the compressor in the low speed operation which is closer to the intermediate condition than the conventional structure, and it is possible to prevent the oil feeding amount from becoming excessive in the high speed condition.

Embodiment 4

A description will be given of a scroll compressor showing a fourth embodiment in accordance with the present invention with reference to FIG. 7. FIG. 7 shows a cross sectional view in the vicinity of the boss portion of the back face of the orbiting scroll.

The structure is made such that the spiral shaped groove 200 b is formed on the inner peripheral surface of the orbiting bearing 103 and the boss portion 120 e, and the throttle passage 202 communicating with the boss portion end surface 120 f is arranged, whereby if it reciprocates astride the seal member 172, the lubricating oil fed to the throttle passage 202 can be intermittently fed to the back pressure chamber 180 from the high pressure chamber 181. On the basis of the constructing means mentioned above, it is possible to increase the feeding amount of the lubricating oil to the high pressure chamber 181 and the back pressure chamber 180 at the low speed, and appropriately control the feeding amount at the high speed, it is possible to improve the efficiency of the compressor in the low speed operation which is closer to the intermediate condition than the conventional structure, and it is possible to prevent the oil feeding amount from becoming excessive in the high speed condition.

As mentioned above, since it is possible to achieve the high efficiency of the compressor and widely reduce the rate at which the oil is mixed into the gas discharged in the high speed condition, by increasing the oil feeding amount in the low speed condition and adjusting the oil feeding amount in the high speed condition, it is possible to widely reduce the oil rising amount which is derived out to the cycle, and it is possible to retain the oil within the compressor. On the basis of the intermediate oil feeding means such as the fourth embodiment, in comparison with the continuous oil feeding means such as the second embodiment, since the same depressurizing effect can be obtained even if a cross sectional area of the spiral shaped groove passage is further enlarged, it is possible to enlarge a dimensional tolerance of the cross sectional area of the spiral shaped groove passage. If the cross sectional area of the passage is enlarged, it is possible to suppress a dispersion of the oil feeding amount in comparison with the first embodiment, it is possible to further simplify a workability, and a cost reduction can be achieved.

Fifth Embodiment

A description will be given of a state in which a winding bush showing a fifth embodiment in accordance with the present invention is expanded to a flat plate shape with reference to FIG. 10. In the case of using a winding bush type bearing material in the orbiting bearing 103, a cylindrical bush shape is formed by rolling a flat plate so as to wind as a cylindrical shape. In a state of the flat plate in a forming process of the winding bush, it is possible to apply a diagonal groove 200 c or a rectangular groove 200 d to the orbiting bearing outer peripheral surface 103 a in accordance with a press molding or an etching process, and it is possible to carry out a process having a further low cost.

In the shape of the winding bush, it is possible to freely set the groove shape, the diagonal groove 200 c comes to the groove 200 b and the rectangular groove 200 d can form the same throttle passage as the groove 200 b, by roll forming the flat plate.

Even in the constructing means mentioned above, it is possible to achieve the high efficiency of the compressor and widely reduce the rate at which the oil is mixed into the gas discharged in the high speed condition, by increasing the oil feeding amount in the low speed condition and adjusting the oil feeding amount in the high speed condition, in the same manner as the cylindrical bearing material in accordance with the first to fourth embodiments.

As mentioned above, in accordance with each of the embodiments, the structure is made such that the sealing means sealing the high pressure chamber in the center portion of the back face boss portion of the orbiting scroll and the back pressure chamber (the low pressure chamber) formed by the internal space of the outer periphery is provided, the spiral shaped passage groove is provided between the inner peripheral surface of the boss portion in the back face of the orbiting scroll and the outer peripheral surface of the orbiting bearing, and the lubricating oil in the high pressure chamber can be continuously or intermittently fed to the back pressure chamber while being depressurized within the spiral shaped throttle passage. In accordance with this, it is possible to widely increase the oil feeding amount in comparison with the intermittent oil feeding only by the conventional small hole, on the basis of the depressurizing effect caused by the spiral shaped groove passage in the low speed operation which corresponds to the intermediate condition, and it is possible to adjust in such a manner as to prevent the oil feeding amount from becoming excessive in the operation of the high speed condition.

Further, since the spiral shaped groove passage is installed between the inner peripheral surface of the turning boss portion and the outer peripheral surface of the orbiting bearing, it is possible to enlarge the cross sectional area at such a degree as to be set longer than the length of the spiral throttle passage in the end plate surface of the orbiting scroll, and it is possible to hold down the dispersion of the oil feeding amount even if the diametrical tolerance is enlarged. The compressor having the lower cost can be provided in accordance with the enlargement of the diametrical tolerance.

Since the sealing means is provided in the end surface of the back face boss portion of the orbiting scroll, and is structured such as to seal the high pressure chamber in the center portion of the back face boss portion of the orbiting scroll and the back pressure chamber formed by the internal space of the outer periphery, it is not necessary to form the high pressure oil reservoir. Accordingly, since the orbiting scroll carried out the turning movement, the lubricating oil having the high pressure is not agitated, and it is possible to reduce the agitating loss, whereby it is possible to provide a compressor having a high efficiency.

It should be further understood by those skilled in the art that although the foregoing description has been made on embodiments of the invention, the invention is not limited thereto and various changes and modifications may be made without departing from the spirit of the invention and the scope of the appended claims. 

1. A scroll compressor comprising: a compression chamber formed by engaging a fixed scroll and an orbiting scroll with each other, each of which has an end plate and a spiral lap provided in a rising manner in said end plate; a crank shaft making said orbiting scroll carry out a turning motion; an orbiting bearing portion engaging said orbiting scroll and an eccentric pin portion of said crank shaft so as to be movable in a direction of a rotating axis and be rotatable and provided in a back face of the orbiting scroll; a main bearing portion arranging a support portion which rotatably engages said crank shaft in a center portion of a frame member; a back pressure chamber zoned by a seal member which is arranged between the back face of said orbiting scroll and the frame member; a high pressure chamber zoned in an inner side of said seal member being maintained at a pressure which is approximately equal to a discharge pressure; and the back pressure chamber zoned in an outer side of said seal member being maintained at a pressure which is lower than the discharge pressure, wherein a spiral shaped groove passage is formed in an outer peripheral surface of the orbiting bearing, and a throttle passage communicating with the back pressure chamber is arranged so as to be provided with such the throttle passage as to be capable of continuously feeding a lubricating oil to the back pressure chamber from the high pressure chamber.
 2. A scroll compressor as claimed in claim 1, wherein the spiral shaped groove passage is formed in an inner peripheral surface of a boss portion in the back face of the orbiting scroll, and the throttle passage communicating with the back pressure chamber is arranged so as to be provided with such the throttle passage as to be capable of continuously feeding the lubricating oil to the back pressure chamber from the high pressure chamber.
 3. A scroll compressor as claimed in claim 1, wherein the spiral shaped groove passage is formed in an outer peripheral surface of said orbiting bearing, and the throttle passage communicating with an end surface of a turning boss portion is arranged so as to be provided with such the throttle passage as to be capable of intermittently feeding the lubricating oil to the back pressure chamber from the high pressure chamber.
 4. A scroll compressor as claimed in claim 2, wherein the spiral shaped groove passage is formed in an inner peripheral surface of a boss portion in a back face of said orbiting scroll, and the throttle passage communicating with an end surface of a turning boss portion is arranged so as to be provided with such the throttle passage as to be capable of intermittently feeding the lubricating oil to the back pressure chamber from the high pressure chamber.
 5. A scroll compressor as claimed in claim 1, wherein said orbiting bearing employs a winding bush which is formed as a cylindrical shape by rolling a flat plate, and a groove which is diagonal in a state of the flat plate or a rectangular groove is applied in accordance with a press molding or an etching process.
 6. A scroll compressor as claimed in claim 2, wherein said orbiting bearing employs a winding bush which is formed as a cylindrical shape by rolling a flat plate, and a groove which is diagonal in a state of the flat plate or a rectangular groove is applied in accordance with a press molding or an etching process.
 7. A scroll compressor as claimed in claim 3, wherein said orbiting bearing employs a winding bush which is formed as a cylindrical shape by rolling a flat plate, and a groove which is diagonal in a state of the flat plate or a rectangular groove is applied in accordance with a press molding or an etching process.
 8. A scroll compressor as claimed in claim 4, wherein said orbiting bearing employs a winding bush which is formed as a cylindrical shape by rolling a flat plate, and a groove which is diagonal in a state of the flat plate or a rectangular groove is applied in accordance with a press molding or an etching process.
 9. A scroll compressor comprising: a crank shaft having an eccentric pin portion; an orbiting scroll having an orbiting bearing to which said eccentric pin portion is inserted; a fixed scroll forming a compression chamber by being engaged with said orbiting scroll; and a volumetric capacity of said compression chamber being changed by pressing said orbiting scroll to said fixed scroll on the basis of a pressure of a back pressure chamber and turning said orbiting scroll on the basis of a rotation of said crank shaft so as to compress a refrigerant, wherein a high pressure chamber is formed between an end surface of said eccentric pin portion and a back face of said orbiting scroll, wherein a throttle passage is provided between said eccentric pin portion and said orbiting bearing, and wherein said orbiting scroll is provided with a discharge passage which introduces an oil to said back pressure chamber from said high pressure chamber via said throttle passage.
 10. A scroll compressor as claimed in claim 9, wherein said throttle passage is formed as a spiral shape. 